1. Field of the Invention
The invention relates to technology in a four-wheel-drive vehicle, which increases switching the reliability and shortens the switching time of a mesh clutch provided in the four-wheel-drive vehicle.
2. Description of Related Art
A four-wheel-drive (4WD) vehicle with a disconnect function is known that is provided with a first mesh clutch as a connecting/disconnecting mechanism that selectively connects and disconnects a power transmitting path between a driving source and a power transmitting member, and a second mesh clutch as a connecting/disconnecting member that selectively connects and disconnects a power transmitting path between auxiliary driving wheels and the power transmitting member. This four-wheel-drive vehicle is able to be selectively placed in a two-wheel-drive (2WD) state in which driving force is transmitted from the driving source to left and right main driving wheels by disengagement of a first mesh clutch and a second mesh clutch, and a four-wheel-drive (4WD) state in which driving force is also transmitted from the driving source to left and right auxiliary driving wheels by engagement of the first mesh clutch and the second mesh clutch. The four-wheel-drive vehicle described in US 2011/0179906 A1, for example, is one such four-wheel-drive vehicle.
In the four-wheel-drive vehicle described in US 2011/0179906 A1, the mesh clutch is not provided with a synchronizing mechanism that synchronizes the rotation on the driving source side of the mesh clutch with the rotation on the power transmitting member side of the mesh clutch. Therefore, the kind of four-wheel-drive vehicle described in US 2011/0179906 A1 is only able to be placed in the four-wheel-drive state when the vehicle is stopped, which is inconvenient and thus problematic. One conceivable way to alleviate this kind of problem is to provide the mesh clutch with the synchronizing mechanism described above.